The disclosure herein relates to fuser members useful in electrostatographic reproducing apparatuses, including digital, image on image, and contact electrostatic printing and copying apparatuses. More specifically, the disclosure herein relates to extended gamut machines or machines having the ability to create specialized colors or coatings. The present fuser members may be used as fuser members, pressure members, transfuse or transfix members, and the like. In an embodiment, the fuser members comprise an outer layer comprising a polymer and deposited thereon, a liquid release agent. In embodiments, the release agent is a blend or mixture of an amino functional siloxane release agent and an alkyl-functional siloxane release agent. In embodiments, the amino-functional siloxane release agent comprises a pendant functional amino group. In embodiments, a non-functional siloxane release agent is used in the blend. The resulting fuser oil enables improved fixing of specialized colors and/or coatings in an extended gamut machine.
In a typical electrostatographic reproducing apparatus, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member, and the latent image is subsequently rendered visible by the application of toner or other marking material. The visible toner image is then in a loose powdered form and can be easily disturbed or destroyed. The toner image is usually fixed or fused upon a support, which may be the photosensitive member itself, or other support sheet such as plain paper.
The use of thermal energy for fixing toner images onto a support member is well known. To fuse electroscopic toner material onto a support surface permanently by heat, it is usually necessary to elevate the temperature of the toner material to a point at which the constituents of the toner material coalesce and become tacky. This heating causes the toner to flow to some extent into the fibers or pores of the support member. Thereafter, as the toner material cools, solidification of the toner material causes the toner material to be firmly bonded to the support.
Typically, the thermoplastic resin particles are fused to the substrate by heating to a temperature of between about 90° C. to about 200° C. or higher depending upon the softening range of the particular resin used in the toner. It may be undesirable to increase the temperature of the substrate substantially higher than about 250° C., because of the tendency of the substrate to discolor or convert into fire at such elevated temperatures, particularly when the substrate is paper.
Several approaches to thermal fusing of electroscopic toner images have been described. These methods include providing the application of heat and pressure substantially concurrently by various means, a roll pair maintained in pressure contact, a belt member in pressure contact with a roll, a belt member in pressure contact with a heater, a drelt (a combination of a drum and a belt) and the like. Heat may be applied by heating one or both of the rolls, plate members, or belt members. The fusing of the toner particles takes place when the proper combinations of heat, pressure and contact time are provided. The balancing of these parameters to bring about the fusing of the toner particles is well known in the art, and can be adjusted to suit particular machines or process conditions.
To ensure and maintain good release properties of the fuser member and to decrease the occurrence of hot offset, it has become customary to apply release agents to the fuser member during the fusing operation. Typically, these materials are applied as thin films of, for example, nonfunctional silicone oils or mercapto- or amino-functional silicone oils, to prevent toner offset.
U.S. Pat. No. 7,208,258 to Gervasi et al. discloses the use of a fuser member and a blend of two different amine-functional polyorganosiloxanes as release agents.
U.S. Pat. No. 7,291,399 to Kaplan et al. discloses a fuser member in combination with a blended polyorganosiloxane fluid wherein fluids with both mercapto-functional and amine-functional groups are utilized.
Clear toner U.S. Pat. No. 9,599,918 to Morales-Tirado et al. discloses a clear toner composition for use in offset printing.
In high-speed color fusing applications, adequate coverage of the fuser member surface is required to meet the demanding environmental conditions and exposure to various levels of toner materials and additives, rapid high temperature thermal cycling and various media composition and weights. Amino silicone release agents are typically used in such high-speed color fusing systems, due to their ability to sufficiently react with the fluoroelastomer surface coatings that are used in conventional fuser member component compositions.
Most high-speed electrophotographic printing systems are embodied by four colors of toner in the development subsystem. These toner colors are most commonly cyan, magenta, yellow, and black. There is a need for expanded color gamut or additional image effects which may include the use of a fifth color station or development housing incorporating the use of clear, white, violet, green, orange, blue, fluorescent, and the like, or toner compositions of custom colors. Additional printing system failure modes may be introduced when expanding a printing system to include a fifth housing for additional toner configurations. In embodiments, high-speed electrostatographic color printing systems include a fifth station to provide a secondary imaging operation whereby added effect or color gamut expansion is enabled by the deposition of a fifth toner after a first fusing step. This results in a thin layer of amine-functional siloxane release agent on the surface of the fused print, which is subsequently re-introduced into the development system and the fusing system a second time. The thin layer of oil on the surface of the fused print inhibits adhesion of the toner from the second printing operation to the surface of the print.
Therefore, is desired to provide a fuser member release agent that provides sufficient wetting, while maintaining and enabling sufficient fix and toner adhesion to prints throughout all steps of a multi-pass printing operation. It is further desired that the release agent results in a decrease or elimination of gelation. It is desired to provide a release agent that inhibits adhesion of the toner from the second printing operation to the surface of the print. Moreover, it is desired that the release agent increase the life of the fuser member, thereby resulting in a cost savings and increased satisfaction to the customer.